TEMPERATURE MEASURING INSTRUMENT

摘要

PURPOSE:To take a high-precision measurement even at a working site where temperature condition is inferior, by converting the resistance value ratio of the resistance bulb and standard resistor of a resistance thermometer into a time ratio. CONSTITUTION:The resistance bulb 2 and standard resistor 3 of the resistance thermometer 1 are supplied with a constant current from a constant current source 4 through a switch 5. A measurement control circuit 7 changes over the switch 5 to the side of the standard resistor 3 or resistance bulb 2. A capacitor 10 is charged up to the voltage corresponding to the resistance value ratio of the resistance bulb 2 and standard resistor 3 and a flip-flop circuit 12 is reset by the voltage. The output of the flip-flop circuit 12 is led to an output circuit 14 through an AND gate 13.